Sliding-clasp fasteners



Dec. 25, 1962 H. PoREPP sLInING-CLASP FASTENERS 2 Sheetsgheet l Filed Feb 5, 1959 Dec. 25, 1962 H, PQREPP 3,069,723

SLIDING-CLASP FASTENERS Filed Feb. 5, 1959 2 Sheets-Sheet 2 INVENTOR /g//m/S /f'o/P P United tates Patent @dice 3,959,723 Patented Dee. 25, 1962 3,059,723 SLIDlNG-CLASP EASTENERS Hans Porepp, Essenredeney, Germany, assigner to Opti- Holding A.G., Glarus, Switzerland. a Swiss firm Filed Feb. 5, 1959, Ser. No. 791,398 Claims priority, anpiicatien Germany Feb. 6, 1958 7 Claims. (Cl. 18-10) The present invention relates to sliding-clasp fasteners made from molecularly-orientable plastic material and has for an object an improved fastener of this general kind.

Sliding-clasp fasteners made of molecularly orientable plastic material, for example a polyamide, polyurethane or the like, are known and in one particular embodiment thereof a stretched plastic flattened thread is helically coiled so that two such helical threads with opposite thread direction may be fixed to textile tapes to form the fastener elements to be actuated by a slider. According to another embodiment a stretched plastic thread having a round cross-section is coiled or disposed helically and on the median longitudinal line the helical pitches of the thread are pressed fiat, in such a manner that these places, after a U-shaped bending of the helices about the median longitudinal line and sewing to a textile Stringer tape, form the coupling parts of two such helices. In both cases the manufacture of the fasteners is relatively complicated, because coiling machines or folding machines must be used which require eccentric or reciprocating movements and therefore are very susceptible to trouble, and moreover the output from these machines is also seriously limited owing to their construction.

In order to increase substantially the output in manufacturing sliding-clasp fasteners made of molecularly orientable plastic materials of the type mentioned, and also to avoid the use of coiling machines or folding machines, the present invention departs from these known arrangements by utilizing the knowledge that the plastic materials in question may, in order to obtain the necessary high degree of strength, be molecularly oriented, not only by stretching, but also by deformation or pressing.

The invention accordingly consists in a method of making sliding-clasp fasteners from polyamide threads or the like in which an unstretched rod or thread of plastic material having any cross-section, but preferably a round cross-section, is stretched, in order to obtain a molecular orientation, by means of a shaping pressure which is exerted transversely to the direction of the thread, there being formed, by means of the shaping pressure, serially disposed teeth having tips, while between the teeth there are formed stretched connection pieces, this thread being subsequently interwoven with or sewn to a textile Stringer tape.

Preferably, the round unstretched plastic rod or thread is fed through two shaping rollers which form the teeth and then, between further shaping rollers, the free ends of the teeth are provided with tips and the side turned away from the teeth is provided with indentations.

By means of this method it is possible to start from unstretched round commercial-type polyamide threads or the like and to subject these to a shaping pressure in a transverse direction, so that thereby the molecular orientation and the high degree of strength necessary for the sliding-clasp fastener are obtained. This pressing into shape is effected by means of shaping rollers so that the thread may always pass rectilinearly or almost rectilinearly through the rollers. Owing to these rotating shaping rollers no parts susceptible to trouble are present and the output may be increased to an unlimitedly high degree in manufacturing the fastener thread, since in practice the rollers may be operated at any desired speed of rotation. By means of such shaping rollers the method may be carried out very simply, the shaped fastener thread even making it possible, in contrast to spiral-thread fasteners and helical thread fasteners, to interweave the thread as a warp thread with the textile stringer tape, because the spacing between the teeth tips always remains the same. On the other hand it is also possible to sew the thread to a textile string-er tape with a simple sewing machine or with a double-chain-stitch sewing machine, the sewing stitches being disposed between the teeth of the thread. Finally, also in contrast to the hitherto known plastic fasteners, a considerable saving of material is effected because the thread need no longer be displaced spirally or helically but proceeds rectilinearly.

The method according to the invention, apparatus for carrying the invention into effect and a sliding-clasp fastener made therewith will now be described with reference to the accompanying drawing which shows enlarged views of the individual parts, and in which:

FIGURE 1 shows a schematic side view of the path of the plastic thread through the shaping rollers;

FIGURE 2 shows a cross-section through the first pair of shaping rollers;

FIGURE 3 shows a cross-section through the second pair of shaping rollers with juxtaposed transporting rollers;

FIGURE 4 shows a plan view of the transporting rollers;

FIGURE 5 shows a partial development of the periphery of the roller of the first pair of shaping rollers in side View;

FIGURE 6 shows the same partial development in plan;

FIGURE 7 shows a modified embodiment of the periphery of the upper shaping roller of the first pair of rollers in a developed partial plan view;

FIGURE 8 shows the polyamide-thread profile in a side view after its passage through the first pair of shaping rollers;

FIGURE 9 shows the final thread profile after its passage through the second pair of shaping rollers in side view;

FIGURES l0 and 11 show partial perspective views of two different thread profiles; and

FIGURE l2 shows a schematic made according to the invention.

ln order to make `the sliding-clasp fastener according to the invention one starts from a preferably round polyamide thread or rod 1 which is unwound from a coil. The thread may also have a different cross-section but the round cross-section is the most advantageous, because it may be lobtained in commerce as an unstretched thread plan view of a fastener in this form. The plastic rod or thread 1 consists of a molecularly orientable polyamide, polyurethane or the like. This unstretched plastic rod or thread 1 passes between two driven rollers 2 and 3 of a first pair of rollers and these two rollers are oppositely located, with a space therebetween, so that the polyamide thread is stretched to the desired extent through shaping by means of the periphery of the shaping rollers. The periphery of the upper shaping roller Z is provided with uniformly distributed teeth 4. These teeth 4, as shown in the development at the top of FIGURES 5 and 6, are offset at the front at 4a and at the rear with a parallel offset flank 4b so that the teeth are generally Z-shaped in cross-section. The offset anks can be obtained by means of a roller having two toothed discs disposed next to each other, one

disc being somewhat displaced in peripheral direction relatively to the other so that, on engagement of these teeth in the polyamide threads 1, the teeth of the polyamide thread 1 are formed as shown in FIG 4. It is however also possible to give the teeth 4 of the upper roller 2 the shape shown in FIGURE 7, which illustrates a development of the periphery of the roller in plan. In

sheaves the case of this tooth construction the front flank is provided with a rib-shaped projection 4c and the rear face with a corresponding rib-shaped recess 4d. It is naturally possible to provide, instead of rib-shaped projections, single or plural projections on the two anlts of the teeth. The flank construction of the teeth of the roller 2 and the flank construction of the teeth of the polyamide thread 1 thereby obtained has the purpose of ensuring that two interengaging polyamide threads with the toothing in question cannot become disengaged transversely to the fastener plane as will be explained hereinafter in further detail.

The lower shaping roller 3 Iof the rst pair of rollers may be constructed as shown in FIGURE 2 in crosssection, i.e. this roller 3 possesses a smooth periphery 3a and has tw-o rside anges 3b which bridge the spacing between the rollers 2 and 3 and also overlap at the side, at least to some extent, the solid core of the shaping roller 2. However, the roller 3 may also advantageously be profiled on the periphery and for example have the profile shown in side view and in plane view in the developments in the lower part of FIGURES 5 and l6. As shown in lthese gures, the roller 3 has projections 5 on the periphery 3a and grooves 6 therebetween, the projections 5 being disposed opposite the tooth gaps between the teeth 4 of the upper roller 2 and the grooves 6 being disposed opposite the teeth 4 of this upper roller. 1f the polyamide thread is pulled through these two shaping rollers, the thread proiile according to FIGURE 8 is produced, i.e. between the thread teeth 7 with the offset iank portions or any other projections on the flanks are disposed arcuate connection pieces 8, the purpose of which will also be explained later.

The pre-shaped thread or rod 1 according to FIGURE 8 arrives between a second pair of rollers 9 and 10 (FIG- URES l and 3), which are also disposed opposite one another and are parallel to the rollers 2 and 3, if the polyamide thread is passed rectilinearly through both pairs of rollers. The periphery of the upper roller 9 is provided with grooves 11, the surface of which is somewhat larger than the external peripheral surface 4e of the teeth 4 of the roller 2 of the first pair of rollers. The external peripheral surface 4e of the roller 2 should moreover be advantageously constructed in a convex manner, in order to dene with lthe cor-operating roller 3 the arcuate form of the connecting intermediate pieces 8. Opposite the previously mentioned grooves 11 of the upper roller 9 of the second pair of rollers are disposed projections 12 of the lower roller 10, the height of which is advantageously somewhat larger than Vthe height of the projections 5 of the roller 3 of the iirst pair of rollers. Between the projections 12 there are again provided grooves 13 which essentially correspond to the grooves 6 of the roller 3. The pre-shaped polyamide thread 1 is fed to this pair of ro-llers 9 and 10 in such a manner that the surface or peripheral face of the pre-shaped teeth 7 is exactly central in the grooves 11. If this thread passes through the rollers 9 and 10 the material is displaced by the projections 12 of the lower roller 10, and thereby the grooves 11 of the upper roller 9 are filled with material in such a manner that the teeth 7 are each provided with an outer mushroom-shaped head 14. If the polyamide thread is not profiled on the side facing away from the teeth 7 by means of the iirst pair of rollers 2, 3, i.e. if the lower roller 3 has a smooth prole, then the projections 12 of the lower roller 10 of the second pair of rollers form suitable impressions situated below the thread teeth 7, and the grooves 13 give the arcuate form of the intermediate pieces 8, this arcuate form being produced on the tooth side by abutments engaging suitably at the side between the teeth. It is further possible according to the invention, if the tooth flanks of FIGURE 6 of the upper roller 2 of the first pair of rollers are offset, also to make the upper roller 9 of the second pair of rollers from two discs which are each provided with grooves 11 on the il periphery and which, `similarly to the offset flanks 4a, 4b (FIGURE 6), are staggered relatively Ito one another. A fastener thread is then finally produced as is shown greatly enlarged in perspective in FIGURE l0.

A pair of transporting rollers 15, 16 are juxtaposed with the second pair of rollers 9, 1t) and move perpendicularly to the rollers 9 and 1G about traverse axes. These transporting rollers 15, 16 are provided on their peripheries with teeth 17 and 18 which engage from both sides between the teeth '7, 14 of the polyamide thread and serve at the same time as abutments during the shaping of the thread by the rollers 9 and 10. The lower side of these teeth 17 and 18 may in this connection also be rounded according to the arcuate shape 3 of the connection pieces between the teeth i of the polyamide thread 1. If desired, an adjoining co-axial disc 19 with a flat periphery is juxtaposed with the toothed transporting roller 16, as can be seen from FIGURES 3 and 4. The periphery of this disc 19 is chosen so that grooves 20 are rolled in one side of the polyamide thread by means of the disc, the sewing-on thread being insertable in these grooves when joining the polyamide thread to a textile Stringer tape as will also be hereinafter explained. Moreover the second pair of shaped rollers 9, 10 with the associated transporting rollers 15, 16 are so constructed that the material of the polyamide thread cannot escape laterally under the shaping pressure. The transporting rollers 15 and 1o and the periphery of the shaping roller itl may also be constructed in such a manner that the connecting intermediate pieces 8 are reduced in width relatively to the teeth 7 and have a rounded cross-section.

After passing through the second pair of rollers 9, 10 the thread has the form according to FIGURES 9 and lO or according to FIGURE ll, or some modified form. In each case the thread is stretched, by the shaaping pressure, to the required extent, so that the molecules are essentially oriented, the teeth with the tips 14 being formed by means of the shaping pressure and the tooth ilanks having gradations 7a on both sides or projections and recesses according to FIGURE ll. Between the teeth is disposed the arcuate connection piece 3, which in certain cases may also extend in a rectilinear manner. One side of this profiled polyamide thread according to FIGURES l0 or l1 is placed as shown in FIGURE 9, against a textile Stringer tape 21, and then the thread With the textile Stringer tape 21 is fed to a sewing machine, preferably to a double-chain-stitch sewing machine, the lower thread of which is disposed on the side remote from the textile Stringer tape. 'I he stitches are made in the tooth gaps, and the double-chain thread thereby becomes located in the grooves 2d, as can be seen from FIGURE 12. It is also possible to use Y-shaped textile Stringer tapes which enclose and are sewn to the tooth bars in V-shape, the sewing stitches being again disposed between the teeth 7. If necessary it is also possible to bring two polyamide threads having the profiling according to FIGURES l() and ll into interengagernent so that the tips 14 of one thread engae behind the tips of the other thread, whereupon these two threads are fed together with two stringer tapes 21 to a double-stitch or double-chain stitch sewing machine the two needles of which sew each polyamide thread to the associated textile Stringer tape 21. In this specific embodiment the upper side and the side of the polyamide thread remote from the tips 14 are free from projecting textile threads or sewing threads so that the slider, when moved, is guided exclusively along the polyamide of the thread which is highly resistant to wear so that a chang of the sewing threads is avoided.

If one side of the polyamide thread is not provided with grooves 20 then it is also possible to sew the thread to a textile Stringer tape 21 in the usual manner, one side of the thread being placed against the textile Stringer tape as shown in FIGURE 9, whilst the other, oppositely disposed side is covered over with a narrow tape in such a manner that it is then possible to effect a sewing with the needle stitches between the teeth on a conventional sewing machine. Also in this case the side facing away from the tips 14 may be exposed whereby, the flange of a slider may be guided against this back, so that also an increased resistance to wear is obtained on using the fastener and the slider.

If the connection pieces 8 of the polyamide threads between the teeth provided with tips are constructed in arcuate shape and if necessary are rounded oif in crosssection, as is explained above, then the teeth of two threads forming a fastener may move in longitudinal direction or the teeth may dilate, if for example a stretching or contraction of the textile Stringer tapes 21 occurs because of moisture. This ensures that a slider will not become locked. Finally it should be mentioned that it is possible to interweave the proled polyamide thread according to the invention directly with a textile Stringer tape.

l claim:

1. A method of producing a sliding-clasp fastener member from a rod of plastic material, said material being permanently deformable by pressure applied thereto, comprising the steps of continuously stamping a series of recesses uniformly spaced lengthwise of one side of the plastic rod to form a series of teeth with connecting rod portions therebetween, then applying pressure to each tooth in turn in a direction transverse to the length of the rod to form a head at the outer end of each tooth, said head having end parts extending beyond each tooth at opposite edges of the tooth lengthwise of the rod, said end parts extending over adjacent connecting rod portions between the teeth, supporting opposite sides of each tooth to prevent spreading thereof while the pressure is being applied to the end of the tooth to form the head, and forming a groove in one side of each tooth while the head is being formed thereon and while the sides of the tooth are being supported.

2. A method according to claim 1, wherein the connecting rod portions are arcuately formed simultaneously with formation of the teeth.

3. A method of producing a sliding-clasp fastener from a rod of plastic material, said material being permanently deformable by pressure applied thereto, comprising the steps of continuously stamping a series of recesses uniformly spaced lengthwise of one side of the plastic rod to form a series of teeth with connecting rod portions therebetween, each tooth having portions offset at opposite sides of the thread so that the teeth are generally Z-shaped in cross-section taken in a plane parallel to the length of the rod, then applying pressure to each tooth in turn in a direction perpendicular to said plane 4to lform a head .at the end of each tooth, said head having end parts extending beyond each tooth at opposite forward and rear edges thereof lengthwise of the rod, said end parts extending over adjacent connecting portions of the rod between the teeth, supporting opposite sides of each tooth in turn to prevent spreading thereof while the pressure is being applied to the end of the tooth lto form the head, and forming a groove in one side of each tooth while the head is being formed and the sides of the tooth are being supported.

4. A method according to claim 3, wherein the connecting rod portions are arcuately formed simultaneously with initial formation of the teeth.

5. A method according to claim 3, wherein each connecting rod portion is arcuately shaped simultaneously with formation of the head on the adjacent tooth and formation of the groove in the side of the tooth.

6. An apparatus for forming a sliding-clasp fastener from a rod of plastic material, said material being permanently deformable by pressure applied thereto, comprising a first pair of spaced coplanar roll-ers for engaging the rod therebetween, one of said rollers having a series of teeth therein and the other roller having a circumferential groove for receiving the teeth of said one roller and for supporting the rod while a series of teeth with connecting rod portions therebetween are formed in one -side of the rod, a second pair of spaced coplanar rollers and disposed forwardly thereof aligned with the first pair of rollers to receive the rod with formed teeth, one roller of the second pair of rollers having a series of shallow, concave peripheral recesses for forming convex heads on ends of the teeth of the rod with head parts extending beyond opposite edges of the rod over adjacent connecting rod portions, the other roller of the Isecond pair thereof having a series of shallow concave peripheral recesses olfset from the recesses in the one roller of the second pair for shaping the connecting rod portions to arcuate form, and a third pair of coplanar rollers disposed perpendicularly to the second pair of rollers, the rollers of the third pair having peripheral teeth for engaging between the teeth of the rod to -advance the same past the second pair of rollers and for supporting opposite sides of each tooth to prevent the same from spreading while the head is lformed thereon.

7. An apparatus according to claim 6, further comprising rod shaping means adjacent to and rotatable with one roller of `the third pair thereof for forming a groove in one side of each tooth.

References Cited in the file of this patent UNITED STATES PATENTS 2,262,881 Boenecke Nov. 18, 1941 2,308,117 Snyder Jan. 12, 1943 2,319,099 Abramson et al. May 11, 1943 2,541,728 Wahl Feb. 13, 1951 2,708,300 Buttress May 17, 1955 2,772,469 Staller Dec. 4, 1956 2,880,488 Macy Apr. 7, 1959 2,939,192 Hansen June 7, 1960 2,979,776 Morin Apr. 18, 1961 FOREIGN PATENTS 874,738 Germany Apr. 27, 1953 1,022,981 Germany Jan. 23, 1958 307,947 Switzerland Sept. 1, 1955 

